2016-12-14 00:32:57

by Max

[permalink] [raw]
Subject: [PATCH] char: lack of bool string made CONFIG_DEVPORT always on

From: Max Bires <[email protected]>

Without a bool string present, using "# CONFIG_DEVPORT is not set" in
defconfig files would not actually unset devport. This ensured that
/dev/port was always on, but there are reasons a user may wish to disable
it (smaller kernel, attack surface reduction) if it's not being used. Adding
a message here in order to make this user visible.

Signed-off-by: Max Bires <[email protected]>
---
drivers/char/Kconfig | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 7ad3127..d647e7e 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -589,10 +589,13 @@ config TELCLOCK
controlling the behavior of this hardware.

config DEVPORT
- bool
+ bool "/dev/port character device"
depends on !M68K
depends on ISA || PCI
default y
+ help
+ Say Y here if you want to support the /dev/port device. The
+ /dev/port device is similar to /dev/mem, but for I/O ports.

config DCC_TTY
tristate "DCC tty driver"
--
2.8.0.rc3.226.g39d4020


2016-12-14 01:06:28

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH] char: lack of bool string made CONFIG_DEVPORT always on

On Tue, Dec 13, 2016 at 04:32:25PM -0800, Max wrote:
> From: Max Bires <[email protected]>
>
> Without a bool string present, using "# CONFIG_DEVPORT is not set" in
> defconfig files would not actually unset devport. This ensured that
> /dev/port was always on, but there are reasons a user may wish to disable
> it (smaller kernel, attack surface reduction) if it's not being used. Adding
> a message here in order to make this user visible.
>
> Signed-off-by: Max Bires <[email protected]>
> ---
> drivers/char/Kconfig | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
> index 7ad3127..d647e7e 100644
> --- a/drivers/char/Kconfig
> +++ b/drivers/char/Kconfig
> @@ -589,10 +589,13 @@ config TELCLOCK
> controlling the behavior of this hardware.
>
> config DEVPORT
> - bool
> + bool "/dev/port character device"
> depends on !M68K
> depends on ISA || PCI
> default y
> + help
> + Say Y here if you want to support the /dev/port device. The
> + /dev/port device is similar to /dev/mem, but for I/O ports.


Hm, did you look at how the indentation for all of the help entries are
in this file? Please match it up to be the same...

Other than that, this looks much better, the format and style of the
submission was fine.

thanks,

greg k-h

2016-12-14 01:26:49

by Max

[permalink] [raw]
Subject: [PATCH] char: lack of bool string made CONFIG_DEVPORT always on

Without a bool string present, using "# CONFIG_DEVPORT is not set" in
defconfig files would not actually unset devport. This ensured that
/dev/port was always on, but there are reasons a user may wish to disable
it (smaller kernel, attack surface reduction) if it's not being used. Adding
a message here in order to make this user visible.

Signed-off-by: Max Bires <[email protected]>
---
drivers/char/Kconfig | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 7ad3127..e8fc493 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -589,10 +589,13 @@ config TELCLOCK
controlling the behavior of this hardware.

config DEVPORT
- bool
+ bool "/dev/port character device"
depends on !M68K
depends on ISA || PCI
default y
+ help
+ Say Y here if you want to support the /dev/port device. The
+ /dev/port device is similar to /dev/mem, but for I/O ports.

config DCC_TTY
tristate "DCC tty driver"
--
2.8.0.rc3.226.g39d4020

2016-12-14 09:00:22

by Geert Uytterhoeven

[permalink] [raw]
Subject: Re: [PATCH] char: lack of bool string made CONFIG_DEVPORT always on

On Wed, Dec 14, 2016 at 2:18 AM, Max <[email protected]> wrote:
> Without a bool string present, using "# CONFIG_DEVPORT is not set" in
> defconfig files would not actually unset devport. This ensured that
> /dev/port was always on, but there are reasons a user may wish to disable
> it (smaller kernel, attack surface reduction) if it's not being used. Adding
> a message here in order to make this user visible.
>
> Signed-off-by: Max Bires <[email protected]>
> ---
> drivers/char/Kconfig | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
> index 7ad3127..e8fc493 100644
>
> --- a/drivers/char/Kconfig
> +++ b/drivers/char/Kconfig
> @@ -589,10 +589,13 @@ config TELCLOCK
> controlling the behavior of this hardware.
>
> config DEVPORT
> - bool
> + bool "/dev/port character device"

bool "/dev/port character device" if EXPERT?

> depends on !M68K
> depends on ISA || PCI
> default y
> + help
> + Say Y here if you want to support the /dev/port device. The
> + /dev/port device is similar to /dev/mem, but for I/O ports.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

2016-12-14 09:11:28

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [PATCH] char: lack of bool string made CONFIG_DEVPORT always on

On Wednesday, December 14, 2016 9:58:53 AM CET Geert Uytterhoeven wrote:
> >
> > --- a/drivers/char/Kconfig
> > +++ b/drivers/char/Kconfig
> > @@ -589,10 +589,13 @@ config TELCLOCK
> > controlling the behavior of this hardware.
> >
> > config DEVPORT
> > - bool
> > + bool "/dev/port character device"
>
> bool "/dev/port character device" if EXPERT?

I think the 'default y' is good enough, there are good reasons
even for non-EXPERT configurations to turn this off.

Arnd

2016-12-14 09:51:13

by Josh Triplett

[permalink] [raw]
Subject: Re: [PATCH] char: lack of bool string made CONFIG_DEVPORT always on

On Wed, Dec 14, 2016 at 10:11:19AM +0100, Arnd Bergmann wrote:
> On Wednesday, December 14, 2016 9:58:53 AM CET Geert Uytterhoeven wrote:
> > >
> > > --- a/drivers/char/Kconfig
> > > +++ b/drivers/char/Kconfig
> > > @@ -589,10 +589,13 @@ config TELCLOCK
> > > controlling the behavior of this hardware.
> > >
> > > config DEVPORT
> > > - bool
> > > + bool "/dev/port character device"
> >
> > bool "/dev/port character device" if EXPERT?
>
> I think the 'default y' is good enough, there are good reasons
> even for non-EXPERT configurations to turn this off.

Agreed. /dev/port seems like something the majority of modern systems
can safely turn off.